Mobile stage vehicles are typically mounted on a rolling chassis and are towed to the site of a performance by a powered vehicle, such as a pickup truck or the like. The mobile stage vehicle is typically set up for a performance or event of relatively short duration and is then dismantled and removed from the performance site for storage. Such mobile stage vehicles may comprise a stage area. Certain of such mobile stage vehicle additionally have deployable canopies and stage sections that comprise shiftable components having substantial mass. It is desirable for individuals performing on the stage that the stage provide a level platform. There is a need to have the chassis of the portable stage vehicle level in order to adequately balance the weight of a deployable canopy and to provide a level reference to insure that an adjoining deployable stage section is flush with the fixed stage portion that is borne by the chassis.
Presently, mobile stage vehicles include ground engaging, variable length jacks to provide a leveling capability. A jack is typically associated with each of the four corners of the chassis of the mobile stage vehicle. An operator utilizes a manual crank to extend or retract each such jack individually. Leveling is done with either a carpenter's level or level bubbles built into the chassis. Achieving a level condition of the stage is an iterative, time consuming exercise because of the interdependence of an out of level condition at one corner of the chassis with one or two adjacent corners, whereby altering the length of one jack affects the level condition of adjacent corners. The jack at each corner of the chassis may be individually actuated by a hydraulic control at the corner. While this eliminates the need for hand cranking the jacks, it does not affect the iterative problem of levelling the chassis through independent actuation of the jacks at the four corners of the chassis.
It would be a decided advantage in industry to have a hydraulically actuated leveling system that would permit leveling of the stage area from a single hydraulic command unit, as distinct from separately leveling each corner (whether by manually cranking the jack up or down or actuating it hydraulically). Additionally, such hydraulic leveling system should provide feedback to the operator of an in level/out level condition. To enhance the safety of the operation, the hydraulic command unit should be physically located away from the chassis of the portable stage so that while major components of the mobile stage vehicle, such as the canopy and deployable stage section, are being actuated.